The connection and disconnection of pipe sections on an oil well drilling rig for drilling oil and deep water wells, test holes and the like is typically accomplished by the use of a cat's head chain device. The chain extends from a motor driven drum, and can be wrapped around a pipe section to engage it. When the chain-wrapping drum is engaged with the motor, the drum pulls the chain to turn the pipe section and screw or unscrew it from another pipe section, depending upon the direction in which the chain was wrapped around the pipe. While this technique enables rapid connection and disconnection of pipe using simple equipment, it is the source of many injuries to workmen. A workman may hold the several turns of chain against the pipe to assure good chain gripping of the pipe, and his fingers may become caught between the chain and pipe. The large forces applied to the chain then can result in serious injury, and in fact this is a common cause of injury in the oil drilling industry.
While it is possible to conceive of a variety of devices that could turn pipe sections in a safer manner, but which operated on a very different manner than a typical cat's head chain, such devices would not be readily acceptable by the industry because cat's head chain devices are already present on drilling rigs and are well accepted as a low cost and effective means for turning pipes. An apparatus which was based on the common cat's head chain device but which helped avoid injury to workmen caused by their handling of chains with their hands near the pipes, would be of considerable value in reducing injuries in the oil well drilling industry.